Concern has been expressed around the potential effect of a new variant strain of coronavirus spreading in Northern Ireland.
The first positive case of the new strain in the region was confirmed on Wednesday.
Meanwhile, 11 more people with Covid-19 have died in Northern Ireland, the Department of Health said on Thursday.
There have also been 841 new confirmed cases of the virus in the last 24-hour reporting period.
Chief scientific officer Prof Ian Young said he is "very concerned" about the new variant of Covid-19 because it is transmitted more easily.
Deputy First Minister Michelle O'Neill urged people to be very careful over Christmas week and follow new lockdown restrictions which will apply from St Stephen's Day.
Prof Young warned if the variant becomes the dominant form it could push the R rate up to 1.8.
"At the moment R is probably sitting between 1 and 1.2, and if we had the variant form and we were all behaving in the same way, R would be closer to 1.6 and 1.8, and that would have severe consequences," he told BBC Radio Ulster's Stephen Nolan Show.
Prof Young said if the variant becomes the dominant form, it would be very unlikely that schools could be kept open.
He said he does not believe that at present the variant is a “major form” in Northern Ireland, but said he is confident there is a small number of cases.
Significantly different
“This particular variant does appear to be significantly different than many of the others which have been in circulation, it has a number of different mutations or changes to its genetic material and those affect the structure of some of the key parts of the virus. As a result it is highly likely that the virus is transmitted more easily than the form of the virus that we have been used to, somewhere between 40-70 per cent more easily transmitted,” he said.
“We don’t think it causes a more severe disease . . . and we are reasonably confident that it will still respond to the vaccine and that the vaccine will protect against this variant form.”
The Stormont Executive issued guidance earlier this week in response to the emergence of the variant, which recommends against any non-essential travel between Northern Ireland and both the Republic and Great Britain .
The executive also agreed to advise anyone arriving in Northern Ireland, who is staying for more than 24 hours, to isolate for 10 days. It applies to anyone who has arrived since December 22nd.
Stay-at-home curfew
Meanwhile, Northern Ireland is set to enter a new lockdown on St Stephen’s Day, of which the first week will be the toughest so far imposed in the region.
A stay-at-home curfew will be in place from 8pm to 6am for that week.
Prof Young urged the public to adhere to the restrictions.
“At the moment I think it (the variant) is only circulating in fairly small amounts, and what we can do to prevent it becoming the dominant strain is for everybody in the next six weeks to adhere really strictly to the mitigations and restrictions that are in place,” he said.
“That gives us the best opportunity of preventing this variant form from becoming established until vaccination begins to take significant effect in our population.”
Ms O’Neill urged the public to follow the new lockdown regulations.
“My appeal is for everyone to strictly follow the Covid regulations and the public health advice and be very careful in all that we do over the Christmas period,” she said.–PA